[Insight-users] Why itk::LBFGSBOptimizer and itk::LBFGSOptimizer are classed as single-variant optimisers?

[Luis Ibanez]

Hi Ali,


1) It is not a "problem", it is an "implementation feature".   :-)



2) It is not in ITK, it is in VXL,

    Please look at the implementation in the file:

         Insight/Utilities/vxl/core/vnl/vnl_lbfgs.h

    Where the optimizer takes as input a vnl_cost_function
    object, that derives from the vnl_unary_function class.



3) It will be great to have multi-variate implementations
    of these optimizers. If you are motivated to write one,
    it will make a great contribution to the Insight Journal.



     Regards,


        Luis



-------------
Ali - wrote:
> Hi,
> 
> The VNL wrappers itk::LBFGSBOptimizer and itk::LBFGSOptimizer are 
> classified as single-variant optimiser, while being based on the 
> quasi-Newton method, they are multi-variant optimisers by nature -- see 
> http://www.alglib.net/optimization/ . Is this the ITK wrapper problem or 
> a VNL issue?
> 
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